

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# This is the list of all pattern aesthetics.
# * List is shared across every geom
# * Not all aesthetics are used by all patterns.
#   is only used by the 'point' pattern.
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pattern_aesthetics <- aes(
  pattern                  = 'stripe',
  pattern_type             = NA,
  pattern_subtype          = NA,

  pattern_angle            = 30,
  pattern_density          = 0.2,
  pattern_spacing          = 0.05,
  pattern_xoffset          = 0,
  pattern_yoffset          = 0,

  pattern_alpha            = 1,
  pattern_linetype         = 1,
  pattern_size             = 0.5,
  pattern_shape            = 1,
  pattern_colour           = 'grey20',
  pattern_fill             = 'grey80',
  pattern_fill2            = '#4169E1',

  pattern_aspect_ratio     = NA,
  pattern_key_scale_factor = 1,

  pattern_filename         = '',
  pattern_gravity          = 'center',   # magick::gravity_types()
  pattern_filter           = '',  # magick::filter_types()
  pattern_scale            = 1,
  pattern_orientation      = 'vertical',

  pattern_phase            = 0,
  pattern_frequency        = 0.1,

  pattern_option_1         = 0,
  pattern_option_2         = 0,
  pattern_option_3         = 0,
  pattern_option_4         = 0,
  pattern_option_5         = 0
)




#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Utils for debugging viewports
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
print_vp_tree <- function() {
  startport <- grid::current.viewport()$name
  on.exit({
    if (startport != 'ROOT') {
      grid::seekViewport(startport)
    }
  })

  # myvp <<- grid::current.viewport()

  while (TRUE) {
    vp <- grid::current.viewport()
    message(
      "-------------- ",
      sprintf("%20s", vp$name),
      "  ",
      round(get_aspect_ratio_from_current_viewport(), 3)
    )
    tmat <- grid::current.transform()
    print(tmat)
    message(
      round(tmat[3, 1]/tmat[3, 2], 3), "  ",
      round(tmat[3, 2]/tmat[3, 1], 3)
    )

    if (vp$name == 'layout') {
      # myll <<- grid::current.viewport()
    }


    if (vp$name == 'ROOT') {
      message("ROOT. done")
      break
    }

    grid::upViewport()
  }
}


#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Utils for debugging viewports
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
verboseGrob <- function(name = "Viewport Tree") {
  delayGrob({
    message("=================== ", name, " ===================")
    print_vp_tree()
    nullGrob()
  }, list=list(name = name))
}


#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#' Create the patterned area to be used in the legend key
#' @inheritParams  draw_key_polygon_pattern
#' @param boundary_df the boundary of the pattern in npc coordinates
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
create_key_pattern_grob <- function(data, params, size, aspect_ratio, boundary_df) {

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # From 'draw_key_polygon', this sets default sizes if none given.
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  data$size <- data$size %||% 0.5
  lwd <- min(data$size, min(size) / 4) * .pt

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Convert the width/height of the key into npc sizes
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  key_native_x <- abs(as.numeric(grid::convertWidth (unit(size[1], 'mm'), 'native')))
  key_native_y <- abs(as.numeric(grid::convertHeight(unit(size[2], 'mm'), 'native')))

  vp <- grid::current.viewport()
  vp_native_x <- abs(diff(vp$xscale))
  vp_native_y <- abs(diff(vp$yscale))


  key_npc_x <- abs(as.numeric(grid::convertWidth (unit(size[1], 'mm'), 'npc')))
  key_npc_y <- abs(as.numeric(grid::convertHeight(unit(size[2], 'mm'), 'npc')))

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # What's the overall scale_factor?
  # The legend is actually drawn in its own viewport with an area of 1x1 npc.
  # I have to do some fancy scaling to draw the current pattern in this
  # scaled viewport as currently appears in the full viewport of the plot.
  # i.e. I need to make the pattern in the legend look like the pattern in the
  # plot.
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  denom <- sqrt(2) * (1/aspect_ratio) * 9/8

  if (vp_native_x/vp_native_y < aspect_ratio) {
    scale_factor <- 1/key_npc_x / aspect_ratio / denom
  } else {
    scale_factor <- 1/key_npc_y/denom
  }

  scale_factor <- scale_factor * data$pattern_key_scale_factor

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Compensate for box the key is rendered in being different aspect ratios
  # i.e. theme(legend.key.width  = unit(2, 'cm'),
  #            legend.key.height = unit(3, 'cm')
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  key_aspect_ratio <- key_native_x/key_native_y
  scale_factor <- scale_factor / key_aspect_ratio

  this_params <- data

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Scale the pattern parameters such that when they're drawn in the key,
  # they will look like what's drawn on the plot
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  this_params$pattern_spacing <- this_params$pattern_spacing * scale_factor
  this_params$pattern_xoffset <- this_params$pattern_xoffset * scale_factor
  this_params$pattern_yoffset <- this_params$pattern_yoffset * scale_factor

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Check if the user has supplied a function to render this pattern
  # If so, get the function render the grobs and return, otherwise check
  # the grid patterns and the 'img' patterns to find the matching pattern
  # generating function
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  pattern_name <- as.character(this_params$pattern)

  user_geometry_funcs <- getOption('ggpattern_geometry_funcs')
  user_array_funcs    <- getOption('ggpattern_array_funcs')

  if (pattern_name %in% names(user_geometry_funcs)) {
    func <- user_geometry_funcs[[pattern_name]]
    pattern_grob <- func(params = this_params, boundary_df = boundary_df, aspect_ratio = key_aspect_ratio, legend = TRUE)
  } else if (pattern_name %in% names(user_array_funcs)) {
    pattern_grob <- create_pattern_array(params = this_params, boundary_df = boundary_df, aspect_ratio = key_aspect_ratio, type = pattern_name, legend = TRUE)
  } else if (pattern_name %in% names(grid_pattern_funcs)) {
    func <- grid_pattern_funcs[[pattern_name]]
    pattern_grob <- func(params = this_params, boundary_df = boundary_df, aspect_ratio = key_aspect_ratio, legend = TRUE)
  } else if (pattern_name %in% names(array_pattern_funcs)) {
    pattern_grob <- create_pattern_array(params = this_params, boundary_df = boundary_df, aspect_ratio = key_aspect_ratio, type = pattern_name, legend = TRUE)
  } else {
    warn("ggpattern - pattern not supported: ", deparse(pattern_name))
    pattern_grob <- grid::nullGrob()
  }


  pattern_grob
}


#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#' Key glyphs for legends
#'
#' Each geom has an associated function that draws the key when the geom needs
#' to be displayed in a legend. These functions are called `draw_key_*()`, where
#' `*` stands for the name of the respective key glyph. The key glyphs can be
#' customized for individual geoms by providing a geom with the `key_glyph`
#' argument (see [`layer()`] or examples below.)
#'
#' @param data A single row data frame containing the scaled aesthetics to
#'   display in this key
#' @param params A list of additional parameters supplied to the geom.
#' @param size Width and height of key in mm.
#' @param aspect_ratio the geom's best guess at what the aspect ratio might be.
#'
#' @return A grid grob.
#' @export
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
draw_key_polygon_pattern <- function(data, params, size, aspect_ratio = 1) {

  # message("draw_key_polygon_pattern(): aspect_ratio = ", aspect_ratio)
  lwd <- min(data$size, min(size) / 4) #* .pt

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Currently not sure, why, but the key_grob is drawn slightly undersized
  # with an offset of "lwd" mm.
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  w <- grid::convertWidth (unit(lwd, "mm"), 'npc')
  h <- grid::convertHeight(unit(lwd, "mm"), 'npc')
  w <- as.numeric(w)
  h <- as.numeric(h)

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # This is a boundary_df polygong the size of the key in npc coordinates in
  # it's own viewport. This is approximately a 1x1 npc unit square.
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  boundary_df <- create_polygon_df(c(h, 1-h, 1-h, h), c(h, h, 1-h, 1-h))


  key_pattern_grob <- create_key_pattern_grob(data, params, size, aspect_ratio, boundary_df)

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # `lineend` is a workaround for Windows and intentionally kept unexposed
  # as an argument. (c.f. https://github.com/tidyverse/ggplot2/issues/3037#issuecomment-457504667)
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  key_grob <- rectGrob(
    width  = unit(1, "npc"), #- unit(lwd, "mm"),
    height = unit(1, "npc"), #- unit(lwd, "mm"),
    gp = gpar(
      col      = data$colour %||% NA,
      fill     = alpha(data$fill %||% "grey20", data$alpha),
      lty      = data$linetype %||% 1,
      lwd      = lwd,
      linejoin = params$linejoin %||% "mitre",
      lineend  = if (identical(params$linejoin, "round")) "round" else "square"
    ))


  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Assemble grob to return
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  grid::grobTree(
    key_grob,
    # verboseGrob("legend"),
    key_pattern_grob
  )
}


#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#' @rdname draw_key_polygon_pattern
#' @export
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
draw_key_boxplot_pattern <- function(data, params, size, aspect_ratio = 1) {

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Create the boundary_df for the rectangular region of the crossbar.
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  xmin <- 0.5 - 0.75/2
  xmax <- 0.5 + 0.75/2
  ymin <- 0.5 - 0.5 /2
  ymax <- 0.5 + 0.5 /2
  boundary_df <- create_polygon_df(c(xmin, xmax, xmax, xmin), c(ymin, ymin, ymax, ymax))

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Create the pattern in this region
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  key_pattern_grob <- create_key_pattern_grob(data, params, size, aspect_ratio, boundary_df)

  key_grob_box <- grobTree(
    rectGrob(height = 0.5, width = 0.75),
    gp = gpar(
      col = data$colour %||% "grey20",
      fill = alpha(data$fill %||% "white", data$alpha),
      lwd = (data$size %||% 0.5) * .pt,
      lty = data$linetype %||% 1
    )
  )


  key_grob_line <- grobTree(
    linesGrob(0.5, c(0.1, 0.25)),
    linesGrob(0.5, c(0.75, 0.9)),
    linesGrob(c(0.125, 0.875), 0.5),
    gp = gpar(
      col = data$colour %||% "grey20",
      fill = alpha(data$fill %||% "white", data$alpha),
      lwd = (data$size %||% 0.5) * .pt,
      lty = data$linetype %||% 1
    )
  )

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Assemble grob to return
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  grid::grobTree(
    key_grob_box,
    key_pattern_grob,
    key_grob_line
  )
}



#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#' @rdname draw_key_polygon_pattern
#' @export
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
draw_key_crossbar_pattern <- function(data, params, size, aspect_ratio = 1) {

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Create the boundary_df for the rectangular region of the crossbar.
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  xmin <- 0.5 - 0.75/2
  xmax <- 0.5 + 0.75/2
  ymin <- 0.5 - 0.5 /2
  ymax <- 0.5 + 0.5 /2
  boundary_df <- create_polygon_df(c(xmin, xmax, xmax, xmin), c(ymin, ymin, ymax, ymax))

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Create the pattern in this region
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  key_pattern_grob <- create_key_pattern_grob(data, params, size, aspect_ratio, boundary_df)

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Generate the box and the line for the crossbar grob separately, as the
  # pattern goes in between the two
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  key_grob_box <- grobTree(
    rectGrob(height = 0.5, width = 0.75),
    gp = gpar(
      col = data$colour %||% "grey20",
      fill = alpha(data$fill %||% "white", data$alpha),
      lwd = (data$size %||% 0.5) * .pt,
      lty = data$linetype %||% 1
    )
  )

  key_grob_line <- grobTree(
    linesGrob(c(0.125, 0.875), 0.5),
    gp = gpar(
      col = data$colour %||% "grey20",
      fill = alpha(data$fill %||% "white", data$alpha),
      lwd = (data$size %||% 0.5) * .pt,
      lty = data$linetype %||% 1
    )
  )

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  # Assemble grob to return
  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  grid::grobTree(
    key_grob_box,
    key_pattern_grob,
    key_grob_line
  )
}




if (FALSE) {
  library(ggplot2)
  library(dplyr)

  plot_df <- mpg %>% filter(manufacturer %in% c('lincoln', 'mercury', 'audi'))

  ggplot(plot_df, aes(x = manufacturer)) +
    geom_bar_pattern(
      aes(
        pattern_angle   = manufacturer,
        pattern         = manufacturer,
        pattern_fill    = manufacturer
      ),
      fill            = 'white',
      colour          = 'black',
      # pattern_angle   = 10,
      pattern_density = 0.2,
      pattern_spacing = 0.03,
      pattern_alpha   = 0.3,
      # pattern_fill    = 'darkgreen',
      pattern_colour  = NA,
      pattern_key_scale_factor = 1.2
    ) +
    # geom_bar_pattern(
    #   aes(
    #     pattern_angle   = manufacturer,
    #     pattern         = manufacturer
    #   ),
    #   fill            = NA,
    #   colour          = 'black',
    #   # pattern_angle   = 10,
    #   pattern_density = 0.1,
    #   pattern_spacing = 0.021,
    #   pattern_alpha   = 0.5,
  #   pattern_xoffset = 0.03
  # ) +
  # theme_void() +
  theme_bw() +
    labs(title = "ggpattern::geom_bar_pattern()") +
    scale_pattern_density_discrete() +
    scale_pattern_manual(values = c(lincoln = 'stripe', mercury = 'crosshatch', audi = 'stripe')) +
    theme(
      legend.key.size = unit(3, 'cm')#,
      # legend.justification = c(1, 0),
      # legend.position = c(0.9, 0.1)
    ) +
    coord_fixed(ratio = 0.25) +
    # facet_wrap(~manufacturer) +
    NULL


  pdf("working/test.pdf", width = 8, height = 4);
  p + coord_fixed(ratio = 0.5);
  # p
  dev.off()

}



if (FALSE) {
  df <- data_frame(
    x = c(0.5, 1, 1.5, 2, 2.5),
    y = sqrt(c(8, 2, 1, 0.5, 0.25))
  )

  ggplot(df, aes(x, y)) +
    geom_point() +
    geom_line()

}













